Smoke consumer



Sept. 10, 1935.` o. MAHAFFEY 2,013,921

SMOKE CONSUMER Sept. 10, 1935. o. MAHAFFEY SMOKE CONSUMER fFiled July 15, 1932 2 sheets-Sheet 2 Q HW www w. s

Patented Sept. 10,1935

SMOKE CONSUMER Oliver Mahaifey, Nashville, Tenn., assigner of one-third to Rose Gill, Nashville, Tenn.

Application July 15, 1932, Serial No. 622,744

9 Claims.

This invention relates in general to furnace devices and more particularly has reference to a smoke consumer.

Previous to this time, the waste products of combustion in the form of smoke from furnaces have constituted an objectionable source of dirt and an economic loss.

It is well recognized that the smoke and soot from furnaces is a public nuisance which it has long been sought to eliminate in many localities. Also, the major portion of the objectionable smoke is possessive of fuel qualities. Thus, at the present time there is a very considerable fuel loss besides the objection to smoke from the cleanliness standpoint, in its discharge to waste.

In the past, there have been devices providing for returning the smoke discharged from a furnace back into the furnace for burning, primarily to conserve in fuel and also to lessenv the quantity of smoke discharged from a chimney. These devices, however, have usually been complicated in construction and operation, and costly, either requiring special furnaces or a very considerable modification of existing furnaces for installation, and have generally proved ineffective.

An object of this invention is to provide an apparatus for consuming furnace smoke.

Another object of this invention is to provide an apparatus for consuming furnace smoke, adapted to any type of furnace, with only a minor modification therein, and without interfering with the normal function thereof.

Still another object of this invention is to provide a single apparatus for consuming smoke, which may be adapted to a bank of furnaces.

A further object of this invention is to provide an apparatus for consuming furnace smoke, automatic in operation.

A still further object of this invention is to provide a simple and inexpensive apparatus for consuming furnace smoke.

With these and other objects in View which may be incident to my improvements, the invention consists in the parts and combinations to be hereinafter set forth and claimed, with the understanding that the several necessary elements comprising my invention may be varied in construction, proportions and arrangement, without departing from the spirit and scope of the appended claims.

In order to make my invention more clearly understood, I have shown in the accompanying drawings means for carrying the same into practical effect, without limiting the improvements in their useful applications to the particular constructions, which for the purpose of explanation, have been made the subject of illustration.

In the drawings:

Figure 1 is a front elevational view, showing my novel apparatus associated with a bank of 5 conventional furnaces;

Figure 2 is a top view of the apparatus;

Figure 3 is a sectional view, taken on line 3 3 of Figure 2;

Figure 4 is a sectional view taken on line 4 4 10 of Figure 1;

Figure 5 is a sectional view, taken on line 5 5 of Figure 4 Figure 6 is a diagrammatic view of the electric 15 control circuit.

Referring more particularly b-y numerals to the drawings, especially to Figure 1, there is shown a pair of furnaces, I and 2, constituting a bank. In this connection, it will be appreciated that while only two furnaces are shown, my novel apparatus to be hereinafter described is adapted for use in connection With one or any number of furnaces..

The furnaces shown are of a conventional type.

My apparatus is adapted to be connected to any 25 type of furnace, or bank of furnaces. For example, my invention is susceptible of application in conjunction with both high and low pressure boilers, small domestic and large commercial furnaces, railway locomotives, ship furnaces, and

in short, any type or horsepower of boiler, chimney, or smoke stack, without interfering with the normal functioning of the appliance on which it is adapted, and without substantial modication therein.

The furnaces shown are covered with brick, indicated by 3, and each provided with a pair of re doors, l and 5, and ash doors, 6 and l. The re doors, 4 and 5, and ash doors, and 7, are

each illustrated as provided with dampers 8.

Above the i'lre doors are shown flue doors 9. Each of the furnaces is shown connected to a stack Il] through conduits Il and I2 for the discharge of smoke therefrom.

In accordance with my invention, I provide for the return of smoke from one or more furnaces for burning as fuel therein. I accomplish this by directing the smoke normally passing'out of the stack, such as I0, having the smoke from one or more furnaces ejected therein, back in whole or in part to the furnace or furnaces for burning with the fuel. This operation, in accordance with my invention, is automatic, and

the smoke is returned to the furnace or furnaces in such a manner as to provide for an eilicient consumption thereof.

In the use of my apparatus, I not only remove the objection to smoke issuing from stacks, by practically eliminating the discharge of smoke therefrom, but provide for great economy in fuel consumption by making use of the very considerable fuel properties remaining in the heretofore useless and objectionable smoke previously ejected as waste, and at the same time do not interfere with the normal operation of the furnace or furnaces. The apparatus I employ is simple and inexpensive, and automatic in operation, and does not require any substantial modification of existing furnaces for installation.

As already stated, I connect my apparatus to a stack from one or more furnaces. This is accomplished, as is best shown in Figure 3, by providing an aperture I3 in the stack II) (a part of the stack being shown in cross-section in this gure). A tapered conduit I4 is superimposed over the aperture I3 in the stack, and suitably connected to the stack, such as by welding. The constricted end of the tapered conduit is terminated in an annular rim I5 for receiving one end of the tubular conduit I6. An automatically operable closure or damper I1 is mounted on the other end of the conduit, and hinged at the top thereof by a pin I8. It will be particularly noted that pin I8 is adapted to be extended through hinges integrally formed on the closure end of the tubular conduit and is movable with the damper. The end of the conduit I6, carrying the cl-osure Il, is adapted to extend through a flange aperture I9 provided in one side of a damper box 2t. The box 2li is provided with a corresponding flange aperture 2l on the opposite side for receiving one end of a tubular conduit 22. The closure Il hinged on the end of the conduit IB is adapted to provide for an automatic damper. The arm 23 having an adjustable weight 24 slidable thereon, is adapted to be fixed to the damper by mounting on the pin I8, the end of the arm being provided with an enlarged portion 25, having an aperture therein for receiving the pin in fixed relation thereto.

'Ihe conduit 22 is provided with an aperture 25 for receiving a tubular member 21 having a manually operable pivoted closure or damper 23 mounted therein, provided with a handle 29. The damper 28 is adapted to provide for an adjustable air inlet for mixing with the smoke returned from the stack. The other end of the conduit 22 is extended through the intake side of a fan or pump 30.

The pump 3E! may be of conventional type, having inlet and outlet ports, and it is only essential in the practice of my invention that the fan be of suicient capacity to break the draft in the stack.

The fan may be operated through any suitable source of power, such as, for example, an electric motor 3I, preferably of the variable speed type, as will later appear, connected to the drive shaft 32 of the fan by a belt or other connecting device 33. The fan 3D as shown in Figure 1, may be mounted on a support 34, xed on the stack, and the motor similarly mounted on a support 35. Manifestly, however, the fan and motor may be mounted in any other suitable manner.

There has thus far been described, the elements of my apparatus connected between a stack for normally discharging smoke from one or more furnaces, and the intake side of a suitably driven fan or pump. There is connected in communication with the outlet port of the fan, an arrangement for directing smoke drawn from the stack by the pump back into a furnace or selectively into two or more furnaces for burning. The return of the smoke is adapted to be carried on automatically, according to predetermined requirements of operation.

One end of a tubular conduit 36 is fitted in the discharge end of the fan as shown in Figures 1 and 2.

The other end of the conduit 36 is extended through an aperture provided in the side of a damper box 3l, similar to damper box 2B already described. An automatically operable closure or damper 38 is hinged on the end of the conduit 36 within the box 37, by a pin 33, extending through hinges integrally formed on the rim of the conduit and the top of the damper. An arm til, like the arm 23, having a weight 4I slidable thereon, is mounted on the end of the pin 39 which is movable with the damper 38 in the same manner as already described with reference to the damper Il. The opposite wall of the damper box 3l is provided with an aperture for receiving one end of a conduit l2 having the other end fixed in one aperture provided in a T $3.

It will be understood from the foregoing description that the dampers I l and 38 are normally closed, but are adapted to automatically open with the creation of a draft in the system by the operation of the fan interposed therein. When the dampers are closed, the then undesirable return of smoke from the stack or bypassing of smoke from the fire box, respectively, is prevented and the draft in the stack thus insured against interruption.

In the assembly illustrated herein, a pair of furnaces is shown. As already pointed out, my apparatus is adapted to one or a plurality of furnaces of any type. It is to be understood, therefore, that in place of the T i3 in the case of an installation in a single furnace, an elbow could be substituted, or a T such as IM, to be later described, having one aperture closed, substituted.

The T 43 is provided with a constricted aperture t5, to which is adapted to be connected one end of a tubular conduit 4S having the lower end connected to a T tl. A manually operable closure or damper 48 having a handle I9 is pivoted in the conduit Il@ for closing off the system to stop smoke returned from the stack l!) from entering the furnace I.

The T 41 is provided with a pair of constricted apertures 5B and 5I for receiving the ends of conduits 52 and 53, having the other ends tted in. elbows 54 and 55 connected to the ends of conduits 53 and 5l. A pair of elbows 58 and 53 are connected to the lower ends of the conduits E55 and 5l.

A pair of novel distributing blocks are mounted within the re box of the furnace, adapted to be connected to the elbows 58 and 59 through conduits 6i) and I5 I, as shown in Figure 2. These distributing blocks indicated by the numerals 62 and 53, as better shown in Figures 4 and 5, consist of tubular bars, round in cross-section, each having a radial projection B4 provided with spaced apertures B5, communicating with the interior thereof. The distributing blocks are adapted to be positioned in the opposite sides of brick fire box walls 66 in recesses, indicated by the numeral l'l, provided therein, and embedded in a refractory cement -or other suitable material,

such as ply brick, indicated by the numeral 68. The blocks are positioned substantially midway on the opposite walls, and on the same horizontal plane.

It will be particularly noted that the faces of t're projections 62 on the blocks are spaced back from the surface of the re walls and apertures 69 for communicating with the apertures 55 provided in the filling material. This insures against damage of the metallic blocks by removal from direct exposure to heat of the furnace.

The operation of the apparatus so far described, will be apparent. Smoke passing from the furnace i into stack lil through the conduit li is selectively drawn from the stack prior to discharge, through the conduits iii, i5, box 28, conduit 22 and pump 38, by the action of the fan. The smoke thus drawn from the stack is returned to the furnace for burning, through the conduit 33, box 31, conduits (i2, 188, 52, 53, 58, and El. The smoke passing through the conduits 5 and 5l is fed into the furnace through the distributing blocks 52 and 63, passing out of the aperture 55 therein, and aperture 68 in the refractory material in which the bars are embedded for even distribution in the re box for consumption as fuel. The smoke normally passing to waste is thus eliminated as a nuisance and consumed as a fuel.

The weights 2d and M are adapted to be adjusted on the arms 23 and 48, respectively, so that the closures or dampers il and 38 movable with the arms, are normally held closed by the action of the weights opening to admit smoke from the stack for return to the furnace only with the operation of the fan 88, by pressure and suction, respectively. The tubular member 2i associated with the conduit 22 on the inlet side of the fan is adapted to provide for mixing the smoke drawn from the stack for return to the furnace with a suitable quantity of air drawn in for mixing with the smoke by action of the fan, the quantity being controlled through adjustment of the damper 28 therein by operation of the handle 29.

As already stated, it is intended to provide for automatically controlling the operation of the apparatus. This may be accomplished in a number of ways. For my purpose, however, as

1 illustrated in the drawings herein, it is preferred to connect a steam line i8 to the boiler 'H in the furnace. The line 'i8 is connected to a steam gauge M with an elbow 'l2 and union i3, as shown in Fig. 1. i

The steam gauge 141 is connected to the union and the steam line i8 is connected through a thermostat device 82 to the conduit l5, connected to a conduit 78 through an elbow Tl. The conduit 'iE has a valve 8| interposed therein and is connected to the thermostat device through a conduit 8@ joined on the end thereof by an elbow 7B. The thermostat device is enclosed in a control box 'I8 also enclosing a switch 88 to be later described. The thermostat device may be of any conventional type which will operate to actuate an electrical switch with a rise in the boiler pressure or temperature. The control used is preferably one best adapted to the fuel employed.

The control device, which may be a pressure control as well as a temperature control, is adapted to actuate an electrical switch within the control box 78 which may be manually operated through the switch handle 88 provided on the box. The switch is electrically connected to the motor 3| and a source of current for operating the same by conductors enclosed in conduits 33, 811i and 85, connected by elbows 86, 81, and 88 respectively between the motor and control box.

With a predetermined rise in temperature or pressure, according to whether a thermostat or pressurestat control is employed, the electrical circuit is adapted to be actuated to operate the motor and through the draft created by the 1 fan initiate the return of smoke from the stack. Correspondingly with a predetermined fall in temperature or pressure, the return of smoke will be discontinued by the circuit being opened in the reverse manner. l

The motor, as already stated, is preferably of the variable speed type with the advantage that the gases in the stack may be handled more advantageously than with a constant speed motor as the load varies caused by heavy or light firing. 2

When a variable speed motor is employed, a variable temperature or pressurestat associated with rheostat or corresponding device is employed so that smoke in increasing quantities corresponding to the increase in temperature or 2 pressure, occasioned by increased nring, may be returned. In this manner a ne automatic regulation is achieved.

The switch within the control box "i8, which is adapted to be operated by the automatic con- 3 trol 82 or by the hand switch 88 in the event that the automatic control is not operating, is also adapted to be actuated by opening of the fire doors 55. For this purpose a conduit 9i) enclosing electrical conductors is connected to 3 the control box i8. Ts 83 and 9i are interposed in the conduit 98, having switches 8i and 92 connected thereto and the arms 85 and @E thereof extending below the tops of the nre doors. In this manner with the opening of the doors 4 the switch arms are adapted to be tripped to operate the switch and discontinue the operation of the motor. When the doors are closed, the motor is actuated by reverse tripping of the switches. The automatic operation of the switch 4 82 may, of course, be discontinued by closing the valve 8l in the steam line from the boiler.

The operation of the circuit will be best understood with reference to Fig. 6. The motor is operated at a variable speed through the expan- 5 sible chamber or other conventional device operating a rheostat. When the temperature or pressure of the boilers, according to the type of device used, is so low as to make operation of the motor inexpedient the circuit will be opened 5D.

as indicated. If the temperature or pressure is sufficient for the rheostat to close the circuit, it may be optionally opened by operation of the hand switch 89, and will be opened and/0I' CIOSed by operation of the switches 9i and 82 through 6 the opening or closing of the nre doors.

As thus far described the operation of my apparatus has been in connection with a single furnace. The automatic control is of course adapted to be extended to a pair or any number 6 of furnaces. This is done by merely providing additional conduits, for example conduit 98, to the boiler in furnace 2 with a valve 8i interposed therein similar to the valve 8l. The conduit 88 is adapted to be connected to the boiler 7 through elements noted by prime numerals corresponding to the elements for connecting the conduit i5 to the boiler in the furnace l. Similarly, the conduit 98 for enclosing the conductors for operation ofthe trip switches by opening of 7 the re doors is extended as are similar switches for the re doors on the furnace 2. In this manner a pair of furnaces may be operated in the same manner as a single furnace or the installation extended to accommodate a greater number of furnaces.

For the purpose of returning the smoke discharged from the stack to a second furnace where a pair of furnaces are used a conduit lll is connected between the Ts llt and 44 on the respective furnaces.

With the operation of the automatic control actuated by the condition of the boilers, the motor will be operated at a predetermined speed according to the condition of the boilers to withdraw desirable quantities of smoke passing to discharge through the stack for return to the lire boxes of the furnace or furnaces for consumption as fuel. As already stated, the motor is also actuated by closing of the iire door on one or more of the furnaces or by manual operation of the switch arm S9. The normal operation of the device is entirely automatic as described, requiring no special or constant attention. It will be apparent that the apparatus is further susceptible for valuable application in connection with automatic stoking arrangements where it would be necessary to give little if any personal attention to the furnace or furnaces.

There is accomplished by this invention an apparatus for consuming furnace smoke adapted to any type of furnace with only minor modications therein and without interfering with the normal function thereof, and also to a plurality of furnaces automatic in operation and simple and inexpensive in construction for conserving fuel and removing the objection to smoke heretofore discharged to waste as a nuisance.

While a preferred embodiment of the invention has been shown and described, it is to be understood that this is given merely to illustrate the underlying principles of the invention, and since these may be incorporated in other mechanical structures we do not intend to be limited to those shown, except as such limitations are clearly imposed by the appended claims.

I claim:

1. A smoke consuming apparatus for a furnace embodying a boiler, a iire box, a stack and a fire door comprising a conduit connecting the stack and the re box, a blower located in the conduit, normally closed draft controlled dampers in the conduit on each side of the blower, an air inlet provided with an adjustable damper in the conduit on the intake side of the blower, means automatically responsive to pressure changes in the boiler to operate the blower at variable speeds to return varying quantities of smoke from the stack to the fire box, said automatic means serving to return increasing quantities of smoke with an increase in the pressure of the boiler, and means operable by opening of the fire door to stop said blower, said means being also operable, upon closing said re door, to permit operation of the said blower.

2. A smoke consuming apparatus for a furnace embodying a boiler, a fire box, a stack, and a fire door, comprising a conduit connecting the stack and fire box, a blower, and normally closed draft controlled dampers located on each side of the blower, and interposed in the conduit, an air inlet in the conduit on the intake side of the blower, said air inlet having an adjustable damper, and means automatically responsive to pressure changes in the boiler to control the speed of the blower, thereby to open the dampers in the conduit and draw smoke from the stack for return to the fire box, and means operable by opening of the i-lre door to stop said blower, said means operable, upon closing said i'lre door, to 5 permit operation of said blower.

3. A smoke consuming system having a plurality of furnaces, each furnace having a boiler, a re box and a re door, comprising a common stack for the furnaces, a main conduit extending 10 from the common stack and through branch conduits extending to the re boxes of the respective furnaces, a blower located in the main conduit, draft controlled dampers in the conduit on each side of the blower, an air inlet provided with 15 an adjustable damper in the main conduit and on the intake side of the blower, manually controlled dampers in the branch conduits for selectively eliminating one or more furnaces from the system, means automatically responsive to pres- 20 sure changes in the boilers for operating the blower to thereby open the dampers in the main conduit and draw smoke from the common stack for return to the iireboxes, and means operable by opening of the re door of any of the furnaces 25 to stop said blower, said means being also operable upon closing said iire door to permit operation of said blower.

4. A smoke consuming system for a plurality of furnaces, each furnace embodying a boiler and a 30 fire box, comprising a common stack for the furnaces, a main conduit extending from the stack and branch conduits extending from the main conduit to the fire boxes of the respective furnaces, a blower located in the main conduit, an 35 air inlet provided with an adjustable damper in the main conduit and on the intake side of the blower, and means automatically responsive to pressure changes in the boilers to operate the blower at variable speeds, whereby varying 40 quantities of smoke are returned from the common stack to the lre boxes of the respective furnaces, such automatic means serving to return increasing quantities of smoke with an increase of pressure in the boilers. 45

5. A smoke consuming apparatus for a furnace embodying a boiler, a fire box, a stack and a re door, comprising a conduit connecting the stack and firebox, a blower connected to the conduit, and means automatically responsive to pressure 50 changes in the boiler to control the speed of the blower to thereby draw smoke from the stack for return to the flrebox, and means operable by opening of the fire door to stop said blower, said means being also operable, upon closing said fire 55 door, to permit operation of said blower.

6. A smoke consuming apparatus for a furnace embodying a boiler, a fire box, a stack, and a re door, comprising a conduit connecting the stack and the fire box, a blower interposed in the 60 conduit, an air inlet on the intake side of the blower, means automatically responsive to pressure changes in the boiler to control the speed of the blower, to thereby draw smoke from the stack for return to lthe rebox, and means oper- 65 able by opening of the i'lre door to stop said blower, said means also operable, upon closing said fire door, to permit operation of said blower.

7. A smoke consuming system for a plurality of furnaces, each furnace having a boiler, a i'lre 70 box, and a fire door, comprising a common stack,

a main conduit extending from the common stack and through branch conduits extending to the re boxes of the respective furnaces, a blower located in the main conduit, an air inlet located in the main conduit and on the intake side of the blower, dampers in the branch conduits for selectively eliminating one or more furnaces from the system, means automatically responsive to pressure changes in the boilers for operating the blower to thereby draw smoke from the stack for return to the re boxes, and means operable by opening of the fire door of any of the :furnaces to stop said blower, said means also being operable, on closing of said re door, to permit operation of said blower.

8. A smoke consuming apparatus for a furnace embodying a boiler, a fire box, a stack and a re door, comprising a conduit extending from the stack to the re box of the furnace and provided with discharge apertures in the re box, such discharge apertures being distributed along each side of the rebox and spaced back from the surface of the re walls, a blower connected to the conduit, and means automatically responsive to pressure changes in the boiler to control the speed of the blower to thereby draw smoke from the stack for return to the re box, and means operable by opening of the re door to stop said blower, said means being also operable, upon closing said re door, to permit operation of said blower.

9. A smoke consuming apparatus for a furnace embodying a boiler, a re box, a stack and a ilre door, comprising a conduit extending from the4 stack and terminating in a tubular metallic member fitted within a recess in a Wall of the re box, such member having a radial projection running longitudinally thereof, through which apertures extend to the interior of the metallic member, said metallic member and projection being embedded in refractory material of the lire box walls, a blower connected to the conduit, and

his OLIVER MAI-IAFFEY.

mark Witnesses to mark:

L. C. PAYNE, H. C. HoLnEsFIELn, 

